This is the first year we start using a HSA. The innitial thought was because DH has an expensive dental implant. And the medical FSA has been decreased to 2500. So we enrolled the HSA plan plus the special purpose FSA (which can be only used for dental and vision). And contributed both to the max.

Now, it just hit me that if we just cash flow the dental implant cost (using up the special purpose FSA, as it will lapse if not used in 2013). And keep the pretax money in HSA plan and let it grow tax free. And later on, we can withdraw the equivalent medical spending amount to pay for whatever we like, and the growth part of the HSA fund to pay for future medical cost tax free.

One suggestion -- keep the receipts for your dental implant (and other medical expenses you pay for with after tax $). You can use them at any point in the future to reimburse yourself from the HSA, in case you need to withdraw cash from it.

yes, that is what I plan on doing. Will have to open a file folder for that. It may be quite a bit of work to save all receipts. Can I scan those? Will IRS take Scanned copy as proof? or I need get shoe boxes ready?